Pneumatic tires are conventionally of an open toroidal shape defining a cavity which is substantially enclosed by the tire, and the closure of the cavity is conventionally completed by mounting the tire on an intended rigid rim. The tire conventionally has a rubber innerliner which is co-existent with and is an exposed surface of the tire cavity. Such pneumatic tire configurations are conventional as would be understood by one having skill in such art.
Pneumatic tires usually rely upon air pressure to maintain their shape and associated performance during service conditions, although some pneumatic tires may be designed to hold their shape and provide representative performance, at least for limited times, even though they may have lost or are not able to maintain their internal air pressure for various reasons. For the purpose of the description of this invention, such tires are considered herein to be pneumatic tires even though they might be designed to run without an internal air pressure for limited periods of time.
For various applications, it may be desirable to provide a pneumatic rubber tire with a sensing device (e.g., transducer and associated microprocessor) on its inner surface which has a capability of transmitting various data relating to the tire such as, for example, its internal air pressure and temperature relative to an external transmitting and receiving device. This device may also have the capability of electronically receiving power generated from an electromagnetic wave generating source outside the tire.
Monitoring equipment is increasingly being used to measure the operating conditions under which pneumatic tires operate. Including but not limited to applications on truck, passenger and off the road (OTR) tires, the monitoring equipment allows for determination of operating tire pressure, temperature of the tire, and distance traveled by the tire, as measured by equipment measuring the number of revolutions of individual tires, among other parameters.
In connection with conducting such monitoring, it becomes important for the monitoring equipment to be installed onto the tire in such a manner that measurements will continue to be obtained over time, and that the monitoring equipment doesn't shift along the mating surface of the tire during operation, or become partially or completely disengaged from that mating surface. Generally, monitoring equipment is installed along the interior surface of the tire on the innerliner.
For example, it may be desirable to provide a tire with a suitable antenna as an actual part of the tire for both receiving various electromagnetic signals from an exterior source by an internal sensing device within the tire, such as a transducer, and for transmitting various electromagnetic signals from within the tire to an external receiving device. For the purposes of the description of this invention, such components which may include one or more of a transducer, associated dedicated integrated circuit microprocessor and other associated component(s), and particularly a transponder, are more simply collectively referred to herein as a microprocessor.
In particular, such antenna may be provided as at least one electrically conductive element. The antenna may be connected, for example, to the microprocessor either physically or inductively, and may be incorporated into an annular rubber strip. Such an annular rubber strip will contain at least one electrically conductive element basically extending substantially or entirely throughout its length (e.g., one or more electrically conductive metal wires) for its purpose and have suitable elastomeric properties for compatibility with the inner rubber surface of the tire.
It would be preferable for the antenna and microprocessor to be incorporated into the tire during the tire building process, to thus securely position the individual devices within the built tire between layers of rubber. The stresses imposed on the devices during the tire building process, however, typically require that the antenna and microprocessor, and similar sensitive devices, be installed after the tire has been fabricated and cured.
During the tire fabrication process, various materials are used in fabricating the tire, such as processing oils, waxes and the like. These materials, incorporated as a part of the green tire, thereafter can interfere with the subsequent procedure of firmly adhering the antenna and microprocessor to a portion of the innerliner. The innerliner surface can be cleaned of such potentially interfering materials by various processes, but the cleaning involves additional time and cost with the prospect for varying results.
Thus, there remains a continuing need to effect a more secure adhesive bond between a surface of the antenna and microprocessor on the one hand, and the innerliner surface of the tire on the other, to thereby minimize the risk of delamination during operation of the tire.